Lithographic press with reciprocating bed and pressure member interrupter



Dec. 13, 1966 0. BRAND 3,

LITHOGRAPHIC PRESS WITH RECIPROCATING BED AND PRESSURE MEMBERINTERRUPTER Flled Jan 21 1965 3 Sheets-Sheet 1 INVENTOR 67/491 [5 5534/113 BY AT ORNEY Dec. 13, 1966 c. BRAN 3,291,045

LITHOGRAPHIC PRESS WIT ECIPROCATING BED AND PRESSURE MEMBER INTERRUPTERFiled Jan. 21, 1965 5 Sheets-Sheet 2 WWIM INVENTOR AT ORNEY Dec. 13,1966 c. BRA 3,291,045

LITHOGRAPHIG PRESS WITH RECIPROGATING BED AND PRESSURE MEMBERINTERRUPTER Filed Jan. 21, 1965 5 Sheets-Sheet :5

52 0 5 5 .26 WAKqkYl FL ,1.:.. 50;" 7353.1" :2? 4 L 5 I u i I I126 I l|/0 I I i I 57 ATTORN EY United States Patent 3,291,045 LITHQGRAPHICRRESS WITH REQIPRQCATING BED AND PRESSURE MEMBER INTERRUPTER CharlesBrand, 1603 Macomhs Road, New York, N.Y. Filed Jan. 21, 1965, Ser. No.426,904 3 Claims. (Cl. 101-146) This invention relates generally to thegraphic arts, and is especially concerned with a unique highly improvedconstruction of lithographic press.

It is an object of the present invention to provide a lithographic presswhich is of increased accuracy and reliability in operation, whereinmovement of the table plate or bed is maintained coplanar andsubstantially dead straight, and wherein pressure of the pressure memberor scraper may be repeatably controlled with precise accuracy.

It is another object of the present invention to provide a lithographicpress of the type described which is extremely safe in use, the tableplate or bed locking in its inoperative position, and which is moreeasily and conveniently operated, as by power or hand crank, including apull-pin clutch in the transmission mechanism.

It is another object of the present invention to provide a lithographicpress having the advantageous characteristics mentioned in the precedingparagraphs, which is neater and cleaner in operation, and which isextremely simple in construction, durable and reliable throughout a longuseful life.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawings,which form a material part of this disclosure.

The invention accordingly consists in the features of construction,combinations of elements, and arrangements of parts, which will beexemplified in the construction hereinafter described, and of which thescope will be indicated by the appended claims.

In the drawings:

FIGURE 1 is a top perspective view showing a lithographic pressconstructed in accordance with the teachings of the present invention.

FIGURE 2 is a transverse sectional elevational view taken generallyalong the line 22 of FIGURE 1.

FIGURE 3 is a partial longitudinal sectional view taken general-1y alongthe line 33 of FIGURE 2.

FIGURE 4 is a sectional elevational view similar to FIGURE 3, butshowing the pressure member in raised position.

FIGURE 5 is a fragmentary sectional view taken generally along the line55 of FIGURE 2.

FIGURE 6 is a horizontal sectional view taken generally along the line66 of FIGURE 2.

FIGURE 7 is a fragmentary horizontal sectional view similar to FIGURE 6,with the table plate broken away.

FIGURE 8 is a sectional view taken generally along the line 88 of FIGURE7, and illustrating an alternate position in dot-and-dash outline.

FIGURE 9 is a partial sectional elevational view taken genera-11y alongthe line 99 of FIGURE 6.

FIGURE 10 is a partial sectional elevational view taken generally alongthe line 10-10 of FIGURE 6, but with the table plate shifted rightward.

FIGURE 11 is a sectional elevational view taken generally along the lineIll-11 of FIGURE 10.

Referring now more particularly to the drawings, and specifically toFIG. 1 thereof, a lithographic press is there generally designated andmay include a base or stand 21 having a plurality of generallyrectangularly arranged, upstanding or vertical legs 22. At their upperends, the legs may be connected together by a pair of laterallyextending, transverse end members 23, and by a pair of longitudinallyextending side members 24.

Fixedly secured and upstanding from the side members 24 are a pair ofelongate, parallel spaced support or frame members 26 and 27. Thesupport members 26 and 27 may each be of angle stock and arranged withupstanding walls in parallel, generally vertical planes, each extendinglongitudinally along and upstanding from a respective horizontal framemember 24, being fixedly secured thereto, as by welding or othersuitable means. Additional rigidifying struts and braces may beemployed, if desired.

The support members 26 and 27 are substantially coextensivelongitudinally; and, a main support roller or pressure roller 30 extendslaterally between the support members 26 and 27 at a medial regionthereof. The main or pressure roller 30 is disposed generallyhorizontal, having stub shafts 31 and 32 projecting axially from itsopposite ends and respectively journaled in bearings 33 and 34 fixed toadjacent support members 26 and 27. The main or pressure roller 30 isthus located substantially in the space between support members 26 and27, extending normal thereto and mounted for rotation about a generallyhorizontal axis. The bearings 33 and 34 are selfaligning ball bearings.

On opposite sides of the main or pressure roller 30 there are providedbetween the supports 26 and 27 auxiliary rollers in aligned pairsgenerally parallel to the main roller. For example, as seen in FIGURE 6-an aligned pair of auxiliary rollers 36 and 37 are mounted on agenerally horizontal shaft 38 extending normal to and between thesupport members 26 and 27 adjacent to a medial region thereof. Leftwardof the auxiliary rollers 36 and 37 is an additional pair of alignedauxiliary rollers 32 and 40 mounted on a horizontal shaft 41 extendingbetween the supports 26 and 27; and leftward of the rollers 39 and 40,there is an additional pair of aligned auxiliary rollers 42 and 43carried by a generally horizontal shaft 44 extending between and normalto the supports 26 and 27. Rightward of the auxiliary rollers 36 and 37,and of the main roller 30, is an additional pair of aligned auxiliaryrollers 45 and 46, mounted on a horizontal shaft 47 extending normal andbetween the side supports 26 and 27, while another aligned pair ofauxiliary rollers 48 and 49 carried by a horizontal shaft 50 extendingnormal to and between the supports 26 and 27 is located rightward of thealigned auxiliary rollers 45 and 46. The main or pressure roller 30, andthe auxiliary rollers 36, 37, 39, 40, 42, 43, 45, 46, 48 and 49 all havetheir uppermost surfaces tangent to a common plane, as may be seen inFIGURE 2.

Mounted on the main or pressure roller 30 and the auxiliary rollers 36,37, 39, 40, 42, 43, 45, 46, 48 and 49 for reciprocatory movement in ahorizontal plane located between the side supports 26 and 27 is a tableplate or bed 51. The table plate is advantageously fabricated of stiff,relatively rigid steel and precision-finished to have substantiallyparallel opposite faces. The table plate is movable between its leftmostposition, illustrated in FIGURES 1 and 6, resting on the auxiliaryrollers 36, 37, 39, 40, 42 and 43, and a rightmost position resting onrollers 48, 49, 45, 46 and 30. The position of FIGURE 2 may be anintermediate position between the above-described leftand rightmostpositions.

In order to assure pure translational movement of the table plate 51,without lateral deviation, close-fitting gibs are secured to respectiveside supports 26 and 27, as at 53 and 54 for sliding engagement withlongitudinal edges of the table plate. The gibs 53 and 54 furtherprovide support to a pair of generally rectangular, relatively lightapron sheets disposed in side-by-side relation and extending across thespace between supports 26 and 27 having their end margins resting on thegibs. The apron sheets 55 and 56 may be hingedly connected together attheir adjacent edges, as by a piano hinge 57; and, the apron sheet 56adjacent to the table plate 51 may be hingedly connected to the end edgeof the latter, as by a piano hinge 58. Thus, when the table plate 51 isdrawn leftward beyond the pressure roller 30, the pressure roller andauxiliary rollers 45 and 46 are protectively covered by the apron sheets55 and 56, for a purpose appearing presently. Upon rightward movement ofthe table plate 51, the hinged connections at 57 and 58 permit the apronsheets 55 and 56 to swing to a depending position just beyond theauxiliary rollers 48 and 49, the sheet 55 depending in FIGURE 10. Thislimits overhand upon rightward table-plate movement.

Carried by the underside of table plate 51, adjacent to the side support26, is an abutment member or block 60. The block 60 is fixedly securedto the table plate 51 by any suitable means, such as fasteners 61, seeFIGURE 9. Secured fast on the inner side of the upstanding side support26, adjacent to opposite ends thereof, are a pair of abutment members orblocks 62 and 63. The abutment members 62 and 63 are fixed to thesupport 26, as by fasteners 64 and 65, or other suitable means, and arelocated in the path of movement of abutment member 60 upon reciprocationof table plate 51. Thus, the abutment member 60 is engageable withabutment members 62 and 63 to limit movement of table plate 51 in theleftward and rightward directions, respectively. In both limitingpositions of movement, the table plate 51 remains stably supported onits supporting rollers.

In order to prevent accidental or inadvertent movement of the tableplate 51, an operating member or handle 67 is carried at one end of thetable plate 51, the lefthand end as seen in FIGURES l and 6, andpivotally connected to the table plate, as by pivotal supports 68 and 69mounting the handle for up-and-down swinging movement about a generallyhorizontal axis. The operating handle 67 is connected to a lockingmechanism, generally designated 70, to automatically lock the tableplate upon downward release of the handle, and require upward swingingof the handle to unlock the table plate for free movement between itslimiting positions.

More particularly, the locking mechanism 70 includes an arm 71 rigidlyconnected to and depending from the pivoted region of the handle 67 forswinging movement between the solid and dot-and-dash outline positionsshown in FIGURE 8. The arm 71 depends to a level below the undersurfaceof table plate 51. Spaced longitudinally inward from the arm 71, a pivotpin 72 is fixedly secured to and depends from the underside of the tableplate 51. The pin 72 is located adjacent to and spaced inward from thelongitudinal side edge of the table plate 51 proximate to the sidesupport 27, and carries a latch member or block 73 for rotation aboutthe generally vertical axis of the pin. The latch member or block 73 maybe of elongate configuration having one end formed with a truncatedcorner or bevel 74, see FIGURE 7. Pivotally connected, as at 75, to thelatch end remote from bevel 74, is one end of a flexible link 76. Thepin of pivotal connection 75 extends generally vertically, and the otherend of link 76 may be connected to the lower end of arm 71 by agenerally horizontal pin 77. The link 76 may advantageously be of stripor bar stock having a medial twist 78 to dispose the link end region 79in a generally vertically plane, and the link end region 80 in agenerally horizontal plane. This affords a sufficient degree ofbendability to the link 76 in all directions.

The handle 67 falls to its lower, solid-line position of FIGURES 7 and 8gravitationally and swings the latch member 73 to the solid-lineposition extending generally normal to the direction of table-platereciprocation, the beveled latch-member end projecting a substantialdistance beneath the adjacent gib 54. A stop member or block 82 is fixedto the underside of table plate 51, as by fasteners 4- 83, in positionto engage the latch member 73 and limit continued downward swingingmovement of the handle 67. Thus, the normal or released position oflatch member 73 is that illustrated in solid lines in FIGURES 7 and 8,as limited by engagement of the latch member with stop member 82. Uponupward swinging movement of the handle 67 the link 76 is shiftedlongitudinally outward and the latch member 73 swung to its phantom,dot-and-dash-outline position, best seen in FIGURE 7. This is anopposite, extreme position of latch-member movement, as limited byengagement of the latch member with the adjacent corner of stop member82. Upon raising of the handle 67, the latch member 73 is swunglongitudinally inward, away from the adjacent side support 27.

Carried by the side support 27 in the region of the latch member 73 whenthe table plate 51 is shifted to its leftward limiting position, as seenin FIGURE 6, is an additional stop member or cam 85. The cam or stopmember 85 is fixedly secured, as by fasteners 86, on the inner side ofside support 27 below the adjacent gib 54 and projects inward into thepath of movement of latch member 73 with the table plate 51 when thelatch member is in its outwardly extending, solid-line position.Throughout the large part of movement of table plate 51, betweenengagement of abutment member 60 with abutment members 63 and 62, thelatch member 73 may project outward toward the side support 27 withoutobstruction. However, as the table plate 51 closely approaches itsleftward limiting position the latch-member surface 74 engages the stopmember 85 to swing the latch member inward. The latch member 73 may thenride over the stop member 85 to a position leftward thereof, as seen inFIGURE 7, when the abutment 60 engages the abutment 62. The latch member73 may then be turned to its outwardly extending position; and, thelongitudinally outer end of stop member 85 may be provided with agenerally oblique or cammed surface 87 engageable with the outer end ofthe latch member to urge the latter toward its limiting outwardlyextending position. This action positively locks the table plate 51against rightward movement, unless the handle 67 is raised to swing thelatch member 73 inward to clear the stop member 85.

Medially of the side supports 26 and 27 are provided upstandingslideways or guides 90 and 91. That is, the upstanding slideway or guide90 is secured by any suitable means to the outer side of support 26, andthe slideway or guide 91 is secured by any suitable means to the outerside of support 27. The guides 90 and 91 extend generally verticallyupward beyond the plane of movement of table plate 51, and arerespectively provided with vertically elongated openings or slots 92 and93. A transversely extending mounting member or bridge 94 is disposedgenerally horizontally over the plane of movement of table plate 51 andhas its opposite ends fixedly secured by any suitable means to the upperends of respective guides 90 and 91.

Disposed beneath the mounting bridge 94 is a laterally extending carriermember or bar 96, having its opposite ends received in respective slotsor slidew-ays 92 and 93 for constrained vertical sliding therein. Alimit member or bar 97 may be fixed to the carrier 96 adjacent to andinward of the guide 90, for sliding engagement with the latter to limitoutward movement of the carrier relative to the guide. Adjacent to andinward of the guide 91, a journal bearing 98 may be fixed to the carrier96 and slidably engageable with the guide 91 to limit carrier movementoutward through the latter. Within the respective slots 92 and 93 ofguides 90 and 91, beneath the carrier 96, are mounted verticallyextending coil compression springs 99 and 100. The spring 99 issupported at its lower end by a mounting bar 101 carrying an adjustmentscrew, and at its upper end engages the underside of carrier 96;whilethe spring 100 is supported at its lower end by a mounting bar 102carrying an adjustment screw, and at its upper end supports the adjacentend of carrier 96. The carrier is thus effectively limited to verticalor up-and-down movement in its horizontal position, and resilientlysupported for such movement by the resilient means or springs 99 and100.

The underside of the carrier 96 may be formed with a downwardly openinggroove 105, see FIGURES 2-4, extending longitudinally of the carrier.Received in the groove and projecting there-from beneath the carrier 96may be a bar 106 having on its underside a scraper or squeegee 107,conventionally fabricated of rubber or other suitable material.Releasable securing means, such as a winged setscrew 108, may bethreaded through the carrier 96 for holding engagement with the bar 106.

Interposed between the bridge 94 and carrier 96 is an operatingmechanism, generally designated 110. The operating mechanism may includea journal block 111 fixed on the upper side of carrier 96 mediallybetween the ends thereof. The journal block 111 may be formed with agenerally rectangular, vertical passageway 11 2 opening upwardly towardthe bridge 94. In addition, on opposite sides of the journal block 111there may be formed a pair of generally vertical slots 113 and 114extending downwardly from the upper end of the journal block andterminating in closed ends substantially level with the bottom wall 115of the passageway 112. A cam block 116 is slidably engaged in thepassageway 112 having its undersurface 117 facing downwardly toward thebottom wall 115 of the passageway.

A shaft 120 extends rotatably through the journal bearing 98 having itsinner region extending through and rotatably received in the lower endsof slots 113 and 114. Carried by the inner region of shaft 120, withinthe passageway 112 of block 111, is a cam 121. The outer end of shaft120 is provided with a transverse arm 122 for manual actuation.

A threaded adjustment pin 124 extends in threaded engagement verticallythrough the bridge 94 having its lower end depending into abuttingengagement with the upper side of cam block 11 6. Secured on theunderside of the bridge 94, surrounding the pin 124 is a bearing orwasher 125 spaced from the bridge by a resilient spacer 126, say ofrubber or the like. Secured on the upper end of threaded pin 124 may bea manual turning arm 127, and threadedly engaged on the pin just abovethe bridge 94 may be a lock nut 128 having a manual turning arm 129.

Connected to the main or pressure roller 30 for effecting positivedriven rotation thereof may be a drive mechanism, generally designated130, see FIGURE 1. The drive mechanism includes a clutch 131 driven bya. chain 132 and selectively engageable with and dis-engageable from theroller 30, as by clutch button 133. The clutch 131 is, of course,connected to one of the shafts of roller 30, say shaft 32. The drivemechanism 130 may be motorized, if desired.

Mounted on side support 27 may be a gear box 134 containing a geartrain, and having a manually actuable rotary handle or crank 135. Thechain 132 is connected by suitable means to the gearing in box 134, sothat rotation of crank 135 is adapted to selectively effect rotation ofroller 30, dependent upon engagement or disengagement of clutch 131.

Shown on table plate 51 is a lithographic stone 137, and a sheet 138adapted to be imprinted.

After release of the locking mechanism 70, as by raising of theoperating handle :67, the table plate 51 may be shifted out of itslocked position to a position resting on the main roller 30. The drivecrank 135 may then be rotated to effect reciprocatory motion of thetable plate on its supporting rollers and constrained against lateralmovement by gibs 53 and 54. With the carrier 96 lowered, as by swingingof the arm 122 to rotate cam 121 from its position of FIGURE 4 to itsposition of FIG- URE 3, and with the pressure member or squeegee 167properly lubricated or greased, the stone 137 is moved beneath thepressure member and the latter assures proper contact of the sheet 138with the stone. By the configuration of cam 121, as best seen in FIGURE3, it will be observed that the cam is in an over-center, stablecondition when the pressure member 107 is lowered. This lowered positionmay be adjusted by vertical shifting of the threaded pin 124. At the endof use, the table plate 51 may be shifted leftwand to its lockedposition, as described hereinbefore, in which condition the apron sheets55 and 56 overlie the rollers 45, 46 and 34 to protect the latter fromdirt and grease.

From the foregoing, it is seen that the present invention provides alithographic press which fully accomplishes its intended objects and iswell adapted to meet practical conditions of manufacture, maintenanceand use.

Although the present invention has been described in some detail by wayof illustration and example for purposes of clarity of understanding, itis understood that certain changes and modifications may be made withinthe spirit of the invention and scope of the appended claims.

What is claimed is:

1. A lithographic press comprising a base, a pair of longitudinallyextending laterally spaced supports fixed to said base, a generallyhorizontal main roller extending laterally between intermediate regionsof said supports and rotatably carried thereby at a [fixed and constantelevation, auxiliary rollers between said supports on opposite sides ofsaid main roller and rotatable about axes generally parallel to that ofsaid main roller, a pressure member directly above said main roller,mounting means mounting said pressure member for vertical movementtoward and away from said main roller, and a table plate resting on saidmain and auxiliary rollers for reciprocatory movement thereon in aconstant plane beneath and on opposite sides of said pressure member,drive means for effecting reciprocatory movement of said table plate onsaid rollers, said mounting means comprising upstanding guideways onsaid supports, a mounting bridge extending spacedly over the path ofmovement of said table plate and fixed to said guideways, a carrierextending between said guideways and mounted therein for upward movementtoward said bridge and downward movement toward the plane of said table,said pressure member being carried on the underside of said carrier,operating means for effecting up-and-down movement of said pressuremember and carrier, said operating means comprising a cam block fixedrelative to said bridge and facing downwardly toward said carrier, a cammounted on said carrier for vertical movement therewith and rotationrelative thereto, said cam being engageable with said block upon camrotation to lower said carrier, resilient means engageable with saidcarrier to urge the latter upward, lockable adjusting means forselectively raising and lowering said cam block, and an actuating leverconnected to said cam for swinging the latter into and out of a stableposition beyond dead center lowering said carrier.

2. A lithographic press according to claim 1, said table plate beingmovable in one direction beyond said main roller, a pair of gibs securedto respective side supports for sliding engagement with longitudinaledges of said table plate, a pair of generally rectangular relativelylight apron sheets disposed in side-by side relation and extendingacross the space between the side supports and having their marginsresting and riding on said gibs, said sheets being hingedly connectedtogether at their adjacent edges by a hinge, and one of said apronsheets being hingedly connected to one end of said table plate formovement therewith on all said rollers in said one direction to ahorizontal position over said main roller and in the other direction toa depending position beyond the auxiliary rollers, said hingedconnections facilitating articulation of said sheets to swing to adepending position by gravity when the sheets pass beyond the auxiliaryrollers.

3. A lithographic press according to claim 1, in combination withlocking means for 'locking said table plate in an inoperative position,said locking means comprising a pair of abutments respectively fixedrelative to said supports and table plate and limiting movement of thelatter to an extreme position in one direction, a stop fixed relative tosaid supports, a latch pivotally mounted on said table plate formovement therewith into engagement with said stop upon table-platemovement in said one direction, and releasable operating means forpivoting said latch to avoid engagement thereof with said stop upontable movement to said extreme position, release of said operatingimeans returning said latch for engagement with said stop to lock saidtable plate in said extreme position, said operating means comprising anactuating member pivoted to said table plate for up-and-down swingingmovement, said latch being pivoted to said table plate about a generallyvertical axis, and a flexible linkage connected between said actuatingmember and latch for swinging the latter to avoid engagement uponraising of said actuating member and for making engagement upon releaseof said actuating member.

References Cited by the Examiner UNITED STATES PATENTS 216,397 6/1879Hamilton 101282 956,807 5/1910 Kirk 101-458 1,380,469 6/1921 Droitcour101-284 1,842,086 1/1932 Hartley 101-269 2,871,782 2/1959 Buttner 10l282X 3,067,676 12/1962 Dickerson 101-146 X FOREIGN PATENTS 978,526 12/1964Great Britain.

ROBERT E. PULFREY, Primary Examiner.

20 J. R. FISHER, Assistant Examiner.

1. A LITHOGRAPHIC PRESS COMPRISING A BASE, A PAIR OF LONGITUDINALLYEXTENDING LATERALLY SPACED SUPPORTS FIXED TO SAID BASE, A GENEALLYHORIZONTAL MAIN ROLLER EXTENDING LATERALLY BETWEEN INTERMEDIATE REGIONSOF SAID SUPPORTS AND ROTATABLY CARRIED THEREBY AT A FIXED AND CONSTANTELEVATION, AUXILIARY ROLLERS BETWEEN SAID SUPPORTS ON OPPOSITE SIDES OFSAID MAIN ROLLER AND ROTATABLE ABOUT AXES GENERALLY PARALLEL TO THAT OFSAID MAIN ROLLER, A PRESSURE MEMBER DIRECTLY ABOVE SAID MAIN ROLLER, APRESSURE MOUNTING SAID PRESSURE MEMBER FOR VERTICAL MOVEMENT TOWARD ANDAWAY FROM SAID MAIN ROLLER, AND A TABLE PLATE RESTING ON SAID MAIN ANDAUXILIARY ROLLERS FOR RECIPROCATORY MOVEMENT THEREON IN A CONSTANT PLANEBENEATH AND ON OPPOSITE SIDES OF SAID PRESSURE MEMBER, DRIVE MEANS FOREFFECTING RECIRPOCTORY MOVEMENT OF SAID TABLE PLATE ON SAID ROLLERS,SAID MOUNTING MEANS COMPRISING UPSTANDING GUIDEWAYS ON SAID SUPPORTS, AMOUNTING BRIDGE EXTENDING SPACEDLY OVER THE PATH OF MOVEMENT OF SAIDTABLE PLATE AND FIXED TO SAID GUIDEWAYS, A CARRIER EXTENDING BETWEENSAID GUIDEWAYS AND MOUNTED THEREIN FOR UPWARD MOVEMENT TOWARD SAIDBRIDGE AND DOWNWARDLY MOVEMENT TOWARD THE PLANE OF SAID TABLE, SAIDPRESSURE MEMBER BEING CARRIED ON THE UNDERSIDE OF SAID CARRIER,OPERATING MEANS FORE EFFECTING UP-AND-DOWN MOVEMENT OF SAID PRESSUREMEMBER AND CARRIER, SAID OPERATING MEANS COMPRISING A CAM BLOCK FIXEDRELATIVE TO SIAD BRIDGE AND FACING DOWNWARDLY TOWARD SAID CARRIER, A CAMMOUNTED ON SAID CARRIER FOR VERTICAL MOVEMENT THEREWITH AND ROTATIONRELATIVE THERETO, SAID CAM BEING ENGAGEABLE WITH SAID BLOCK UPON CAMROTATION TO LOWER SAID CARRIER, RESILIENT MEANS ENGAGEABLE WITH SAIDCARRIER TO URGE THE LATTER UPWARD, LOCKABLE ADJUSTING MEANS FORSELECTIVELY RAISING AND LOWERING SAID CAM BLOCK, AND AN ACTUATING LEVERCONNECTED TO SAID CAM FOR SWINGING THE LATTER INTO AND OUT OF A STABLEPOSITION BEYOND DEAD CENTER LOWERING SAID CARRIER.